Japanese Patent Application Publication No. 2016-149841 describes a charger for charging a battery pack of an electric power tool. This charger includes a housing which includes an intake port and an exhaust port, a battery interface which is provided on the housing, a charging circuit which supplies charging power to a battery pack attached to the battery interface and a blower which introduces air into the housing through the intake port and exhausts air to outside of the housing through the exhaust port. In this configuration, an interior of the housing is forcefully ventilated by the blower, and thus an increase in a temperature of the charging circuit is reduced.